Why I’ve switched to an oval chainring.

I’ll admit that I wanted to hate it. When the Absolute Black oval chainring actually showed up in the mail I knew I was going to have to try it out but I sure as hell didn’t expect to keep it on my bike. I mean, everyone knows that oval chainrings suck and that the industry already tried it with the infamous BioPace rings that Shimano tried to pass off on us.

Having ridden bikes for 15+ years and spending several of those in a bike shop as a mechanic, I’ll admit that I helped to spread that story. But who could blame me – several years back I had pedaled a few BioPace equipped bikes around the parking lot to check them after a tune up and they really did feel funny and not at all what I would want on the trail.

Now fast forward to a couple months ago when I got an email from someone telling me how much he loved his oval chainring. He said that you could get oval chainrings that were much different than what BioPace felt like and that they actually helped on the trail.

Of course, I’d heard this before but I never believed it. For the last few years I’d heard that there was a new generation of oval chainrings that were supposed to fix the problems that plagued BioPace. But I figured this was just another handful of magic beans and never paid it much thought.

However, there was something much different about this email. This guy liked his oval chainring so much that he wanted to send one to me as a thanks for all the help he had gotten from my blog over the years. I figured I couldn’t claim to be objective and not even try it so I agreed. I told him the size chainring I needed and promised to try it out when it showed up.

And, like I said, it did indeed show up. After letting it sit on my desk for a week I finally decided to take it into the shop to get it put on and endure the questioning looks and comments that I knew were sure to come. By this point I was actually pretty curious about what it would really feel like and so I was prepared to put up with a little good natured ribbing.

So I dropped it off and explained that I was trying it out to see how it felt on the trail but that they should hang onto my other chainring for me. I figured I’d get one or two rides in and be ready to switch back. I don’t like to feel like I’m being held back by my bike on the trail and I’ll only endure so much to “check something out” before I go back to what I know works.

After waiting a couple days I got the text that my bike was “ready to shreddy”. I went to pick it up and take it on its first ride, my curiosity piqued at this point. I was really looking forward to just getting into the parking lot for a few hard pedal strokes to see what I was going to be dealing with.


Fully prepared to turn around and give it back to the shop to have them take the oval chainring off, I went into the parking lot and laid down those first few pedal strokes. I was ready to feel some weird spot in the pedal stroke where the tension would feel funny for some reason. But it didn’t feel too bad. A little different but not bad.

So I decided to step it up a notch and take it out on the trail. Again, I couldn’t put my finger on it but it did feel slightly different…but not in a bad way. In fact, as much as I hated to admit it my pedal stroke did feel smoother.

Still not convinced I took the bike home and didn’t say much to anyone about it. I wanted to get a few more rides in and get back on a round chainring to see what difference I felt on it once I had some time on the oval chainring. I still figured I’d go back to the round chainring eventually but my first ride was intriguing enough to warrant some more “research”, a.k.a. trail rides.

That was a few weeks ago and I’ve still got the oval chainring on my bike. What’s more, I don’t plan on taking it off anytime soon. After getting used to it and trying out a round chainring I can really feel how it smooths out the power spike that you get from your pedal stroke. This power spike is one of the major factors you have to control on loose, technical climbs and so this means you don’t have to work as hard to maintain traction.

It also smooths out the pedal stroke in general and you can feel your legs working more efficiently. Since you are not having to push as hard at the top where you are weakest you don’t have to expend as much energy and it is easier to get momentum into the pedal stroke. But the chainring ramps up the tension as you get to the strongest parts of your pedal stroke, allowing you to take advantage of your legs natural strength curve.

If you think about it, it is trying to accomplish the same thing that some people claim is the reason they pull up on the backstroke – to maintain “even tension on the pedals”. By pulling up and pushing down at  the same time you lessen the power spike into the pedal, making it less likely you will spin out on a climb. However, as the studies I have referenced in the Flat Pedal Revolution Manifesto tell us, when you apply this technique you sacrifice power and efficiency.

The oval chainring looks to accomplish this same task but from a different angle. Instead of asking you to pedal in a sub-optimal fashion to compensate for the uneven power transfer, you change how that power is being transmitted into the drivetrain. You change the machine to accommodate how the human optimally moves, not the how the human moves to accommodate the machine. This allows you to continue to pedal in your strongest, most efficient manner possible while smoothing out how that pedal stroke is transmitted into the drive train.

This goes for both seated and standing pedaling – I was a little worried that it would mess with the “feel” of standing pedaling too much but it feels just fine. In fact, there has not been a single instance on the trail where I’ve missed my round chainring.

Now, with all of this said I need to reel it back in a little bit. I’m not saying that you “need” an oval chainring. Most of the time I can’t tell a difference between the round and oval chainring but there are a few spots where I can feel myself not having to lock down as hard on climbs to maintain traction or I have a little bit easier time pedaling out of a spot where I got stuck in a higher gear than I wanted.

In other words, it isn’t a night and day difference like going from a fully rigid bike with cantilever brakes to a modern full suspension bike. More like going from a good 26” bike to a good 27.5” bike, the differences are subtle…but they are there.

So if you are in the market for a new chainring or are interested in gaining a legit efficiency advantage on the trail I’d recommend checking out the Absolute Black oval chainrings. There may be other good ones on the market but theirs is the only one I’ve tried and so it is the only one I can vouch for. Like me, you may just find you were handicapping yourself based on nothing but public opinion.

Until next time…

Ride Strong,

James Wilson

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  1. Rafael says:

    Hi James,

    This is so funny, just yesterday I was thinking of writing you and asking on your take on the oval rings.
    Now I know 🙂

    Best regards

    Reply • September 8 at 10:47 pm
  2. John says:

    These things come in degrees of offset. Can you explain how you would choose which degree is right for your stroke?

    Reply • September 9 at 9:36 am
    • bikejames bikejames says:

      I’m not sure but according to the Absolut Black website they calculate that for each chairing size.

      Reply • September 9 at 12:04 pm
  3. Arlo Svoboda says:

    I ride Rotor oval rings on 2/3 of my bikes and completely agree with your assesment. You don’t need them, but once you try them, you won’t go back to round. Why did you have to drop your bike off at the shop to change out the ring? That’s a 10 min job that took the shop 2 days!

    Reply • September 9 at 9:47 am
    • bikejames bikejames says:

      It is an easy enough job but sometimes I just like to have someone else worry about it for me. I also know that 10 minute jobs have been known to turn into 60 minute jobs on a bike. I have a good shop I like to go into and I told them it wasn’t a big hurry since I was busy for a few days and couldn’t get out and ride anyways.

      Reply • September 9 at 12:06 pm
      • Arlo Svoboda says:

        Support your local LBS!

        Reply • September 9 at 12:28 pm
  4. Dag says:

    James I have been intending ask your opinion on the oval chain rings for a couple of weeks – but just as well I waited, since now you have actually tested it yourself. I changed to the Absolute Black oval 32 teeth about 8 weeks ago. Well, four weeks after I got it, I bought myself a second one – a 34 teeth which would be more suitable for a fast off road (not single track) 100km ultra marathon that I plan to race. I think that speaks for itself as far as my experience goes on the AB oval. Firstly, I have thus far had no obvious reason to switch back to a round ring. I have tested it on steep single track sections that i am well acquainted with and that were hard to get up with the same size round ring. if any different, the oval made it easier to get up the challenging gradient. It also seems that I am less likely to spin out, hence a smoother transfer of power over the 360 full circle (without pulling on the pedals, or using flat pedals). I also seem to feel less fatigued on the same climb at the same effort. I was concerned about high cadence possibly being negatively affected by the oval, but it does not seem to have any significant effect on that aspect either. I still have my old Shimano BIO-PACE ovals on my road bike – these are a disaster so please do not relate the new AB oval rings to Bio-Pace – they are in fact the complete opposite design…

    Reply • September 9 at 1:23 pm
  5. Leonard says:

    I’ve been using AB 32t oval for the past month. I came from a 30t NW. Even though the AB ring is larger, it felt easier to pedal compared to the smaller 30t. Pedaling on flat land doesn’t prove much difference (could just be me though), but pedaling uphills whether standing or seated felt easier and consequently quicker. My currently on a hardtail and if I were to build a full suspension I’d definitely get AB oval for it.

    Reply • September 9 at 4:51 pm
  6. Leroy says:

    Bought one to hopefully hope with knee pain and after one long hard ride I instantly bought another for my hardtail! I didn’t realize how much I really liked it till I was at the LBS and took a new bike for a test ride. I kept thinking the bike pedaled like crap and couldn’t figure out why it felt so horrible, then it dawned on me, it was the round rings… Bought the bike, put my cranks and chainring on it and loved it ever since.

    I find the rings help most on technical or loose climbs. Sometimes the cranks can feel a little odd if you are in too low of a gear at a high cadence. I find I often run a gear higher and longer than I did with round rings. Sprinting (standing) at high cadence can be a little awkward at times as I feel my legs don’t get the slight break between hard pushes that they did with a round ring, but I think this is partially because I have rather large legs and its hard to get them moving that fast?

    Overall a believer and will probably even order one for my dirt jumper so all my bikes feel the same…

    Reply • September 10 at 9:28 am
  7. mike mooneyham says:


    Reply • September 12 at 7:42 pm
    • bikejames bikejames says:

      And yet it isn’t…don’t make the mistake I did and go based on nothing but public opinion and not your own experience.

      Reply • September 13 at 2:41 pm
      • Mike says:

        Been riding longer than you have been alive. I base all my comments on experience. Come again? BioPace. They are reinventing the wheel.

        Reply • September 19 at 11:36 pm
        • bikejames bikejames says:

          So you’ve tried the Absolute Black oval chainrings? Once again, if you have not tried them then you are basing your opinion not on experience but public opinion. That is the mistake I made. If you have not tried them then don’t compare them to BioPace until you do because you have no experience to base that opinion on.

          If you have tried the Absoute Black chainring then what did you not like about them and how did you find them similar to BioPace? I’ve ridden both types of rings myself and find it hard to believe that you can’t tell the difference between them, I though that they feel nothing alike.

          Reply • September 20 at 8:26 am
        • Patrick says:

          Try it, you’ll be surprised, sometimes change is good, especially when learning from experience…. Biopace….

          Reply • May 1 at 4:57 pm
  8. David Joslin says:

    I am pretty shocked. Mounted up the oval ring and rode my normal training trail. 50:24 vs my previous best of 52:20. I did not feel particularly good today and am actually getting over a cold. It tool me only a mile to get used to it. What really sold me was the sound on pavement and loose dirt. It am used to my tires making a pulsing sound as I pedal and that pulsing was significantly less. I am really looking forward to more diverse rides, but so far, I am enthralled with the oval rings. I went with AB 32t 104bcd ring.

    Reply • October 5 at 10:18 pm
  9. Andrew says:

    Maybe there is some reason why it wouldn’t work, but I would like to try an oval ring that is even more oval. I wonder what is the point where it starts to feel weird or it messes with the rest of the drivetrain.

    Reply • October 6 at 3:01 pm
  10. Richard says:

    Great review,
    If I’m using a 1×10 setup with a 32 up front what tooth size would I use on an oval? Same or more?

    Reply • October 11 at 10:07 pm
    • bikejames bikejames says:

      Yeah, that is what I would use.

      Reply • October 12 at 1:59 pm
  11. WanRahimHashim says:

    Hi..Where can get this in Malaysia ? T’q

    Reply • October 16 at 8:38 pm
  12. H. Ribeiro says:

    Please, option language…..Portuguese!

    Reply • October 20 at 6:37 pm
  13. Carl says:

    Have you had any issues with lack of chain tension or your chain coming off? I imagine the chain tension would be inconsistent with an oval ring. The reason I’m curious is my current 1×10 setup has an issue with chain tension. I can’t shorten the chain any more, nor tighten the rear mech clutch, due to the configuration. When in my two smallest cogs on the cassette the chain runs slacker and sometimes comes off. I’m thinking an oval chainring might make this worse. I might need to look at a chain guide. Any thoughts?

    Reply • October 28 at 5:11 pm
    • bikejames bikejames says:

      No, I have not had any problems. I just rode my bike down Porcupine Rim yesterday and never had my chain give me any problems.

      Reply • October 29 at 11:18 am
    • henrique says:

      Hi Carl. I’m training with oval for two months and it’s pretty interesting. And I had the same problem described by you on first day. I use a 1×10 setup too and the two last smallest cogs always dropped, specially if a put too much power (wheeling for example).

      Solution 1: Some derailleurs have I tension adjustment that could be used if you chain is lack tension. Shimano XT for example has a small button (on|off) that can apply additional tension. If your derailleurs don’t have this button some can still do it by adding tension on the coil.

      Solution 2: “Shorten your chain”. Use a Chain guide so to adding tension so it looks like that the chain was shorten. Some chain guide, as mine, must be adapted to work well on oval, I turned mine a little bit.

      Reply • December 25 at 7:08 am
  14. William Madden says:

    Kinda wondering if this oval chainring could help me with a significant injury I received that left me with diminished nerve reception in my left foot and gastric muscle (specifically, loss of dorsal flexion that diminishes my lower stroke and getting it back around to mash it again). I developed a brace that allows me to mash the pedal without my foot caving down due to the lack of signal to hold it stiff when coming down on the pedal. I race BMX and the first few pedals out of the gate are the most crucial.
    So, do you see any help in this problem I have? Would the oval assist in any way getting the quicker upstroke to downward force?

    -Bill Madden

    Reply • April 16 at 11:16 am
    • bikejames bikejames says:

      I’m not sure but it might. It makes it “easier” to turn over at the hardest part so it wouldn’t put as much strain on the foot. I’d say try it out and see, I certainly don’t think it would hurt.

      Reply • April 17 at 2:36 pm
    • Joseph Dowski says:

      Hi Bill,
      I have a similar neurological “foot drop” condition in my right foot where I can barely pull up with my foot/toes. I have run oval chainrings on my road bikes and can definitely vouch that they will help smooth out your spin and get you through the dead spot in your pedal stroke. And if you haven’t done so already, move the cleats as far back (towards your heel) as they can go on your shoes if you’re running clipless. 🙂

      Reply • June 28 at 5:00 am
      • bikejames bikejames says:

        Thanks for the feedback on that.

        Reply • July 4 at 10:46 am
  15. William Madden says:

    *gastrox muscle

    Reply • April 16 at 11:17 am
  16. Michael Reimer says:

    Great article. I was unsure about this product, but now I NEED to try this after reading your article and the comments associated with it. AbsoluteBlack stated on fb that you have a discount code available to provide us. That would be great if you do, but I am going to purchase even if you don’t. Great info, thank you.

    Reply • May 7 at 7:49 pm
    • bikejames bikejames says:

      Sorry but I don’t have it anymore, to be honest you are the first person who ever asked for it and I’m not sure where I put it. You might try emailing them and seeing if they’ll give it to you but either way it is worth checking out.

      Reply • May 9 at 12:03 pm
  17. Pau says:

    Hi James! I want to put an AB oval chainring on my bike. I do XC races and I’d like to ask you, if I ride a 26er bike, Is OK to put a 36t oval chainring with 11-42 rear?

    Reply • May 24 at 12:24 pm
    • bikejames bikejames says:

      I’m not sure, you’d have to get in contact with the guys at Absolute Black to see.

      Reply • May 25 at 1:40 pm
  18. henrique says:

    I start to use oval but I lost balance too fast while wheeling, I must do a strong short pedal to keep the wheel up. It’s not a fluid natural movement as before but like a old truck climbing uphill, a sequence of harsh movements.

    Does anyone feels the same?

    Reply • December 25 at 7:22 am
  19. Chris King says:

    James, are you still riding oval?

    Reply • April 16 at 12:47 pm
  20. Rob Jamieson says:

    Preaching to the converted!
    I fitted the same chain ring about 3 months back. probably got a thousand plus miles on it now. I love the extra power it gives me, especially on the climbs. fully recommended from me.

    Reply • April 26 at 8:49 am
  21. Joseph Steel says:

    This is really interesting. When I got my wife into mountain biking some years ago she struggled with her peddling. She rode fairly well, but always said she just found her peddling felt like something wasn’t right.

    Her bike was a ’01 Giant NRS 16.5 that came with 175mm cranks. My wife is 5’6″ with the typical female body of shorter legs/longer torso… So I change them for 165mm Shimano XTRs (one of the good things about buying older bikes… top-of-the-line equipment on the cheap)… Also an XTR BB… Updated both the RD and the FD to newer XTs (newer in 2010)… Put on a longer stem… Wider handlebar… Switched wheels to Mavic tubeless rims with WTB Weirwolf. And also changed her cog to a Shimano 12/36 cog.

    She was happy… Her bike got even lighter (except for the cog)… She was pretty fast on it… But the peddling issue for some reason still niggled at her.

    Then one day by chance I came across an article about oval rings… The good and the bad about them… But the good seemed to address what she was talking about so I decided to give it a try and bought a used set of Rotor Q oval rings off eBay for her.

    I got a LBS to install them and on her very first trail ride she was like “YES!”

    Fast forward… We both stopped riding for the last three+ years and I sold our bikes thinking our riding days were over… But this year the bug bite again and I bought her a ’06 Cannondale Prophet — which she hated… Said the peddles felt like they were behind her (I know, what’s up with her and peddling).

    Anyway, I then found a ’13 GT Sensor for a great price and bought that for her. Immediate love… Her first reaction was that peddling was easy (an endorsement for GT’s Independent Drivetrain™ Suspension System design I guess).

    But then… This weekend when we were out on a local trail she reminded me of the “special ring things” I bought for her that she really loved.

    And that’s how I came across your blog post… Researching “special ring things” for my wife.

    Strange… I made all sorts of upgrades to her Giant NRS… But the only one she specifically remembered was the “special ring things” I put on.

    Oh yes… And the Planet ARS ladies saddle.

    Well… She also let me know that her new bike is heavier than her old yellow and black “Speed Racer.”

    What can I say, I created a monster.

    But my main point is… There definitely is something about oval rings… And I’ll be ordering two sets this time around.

    Thanks for the article Bikejames.

    Reply • May 9 at 2:27 pm
    • bikejames bikejames says:

      Thanks for the story and feedback, glad you liked the article.

      Reply • May 11 at 11:02 am
  22. Alan W says:

    A good article and subsequent comments. Now in my 60’s I look for whatever I can to help out. I recently switched my Trance from an 11-36 to 42 and put an Absolute Black 30 oval on the front. Yeah I love it but I have a couple of observations I don’t understand. I’m tall anyway at 6’2″ but even though I have a 125 dropper I raise the saddle still higher before any long haul climbs, and I definitely feel the oval shape on these climbs AND on short maybe 50 m steeps where I stand up half way up the slope. The Trance is a good climber anyway but even better imo now. The rest of the time I wouldn’t consciencly know its there. I’ve swapped over with buddies on climbs to get their thoughts and they agree, in fact a couple of the guys just over half my age say I’m cheating it seems so easy, on the long hauls at least.

    Reply • November 13 at 12:09 am
  23. Marcus M says:

    I heard about oval chainrings not too long ago actually, and what I heard about them is that they made pedaling easier. This article simply confirms that. My point is, I’ve been looking at getting one because I have terrible issues with climbing. I feel like I’m having to put way too much effort into pedaling my 35-40lb machine up the trails, cause I’ve hauled 105lbs up a 10% grade (and boy was it a burner), on a 25lb road bike, towing about 80lbs. Factor in my then 110 lbs (at 19 mind you, I was not a healthy lad. I’m 23 now, weigh in at 135lb, and am still not very healthy), and I pulled a full 225lbs. I want to have that kind of capability while I train for some harder rides.

    Reply • July 18 at 8:56 am
  24. The realist says:

    I have been a cyclist all my life, alongside playing football and jogging, all mainly to keep fit. I have rode many different mountain bikes and being close to the english lake district there are lots of seriously steep hills and mountains to climb and I always found them seriously challenging, I would always have to stand up on the pedals and use my bodyweight to have any chance of getting over the summits and it was always hard work and gruelling and no matter how fit I was it never got any easlier I always had to revert to this technique. I went through a period of about 10 years without using a bike and became really unfit by my standards and in my early 40’s I was given an old specialized bike, the stickers had mostly worn off but I think it was a 1990 Rockhopper, which I restored and kept as much of the original parts as possible. Anyways I didnt know anything about Biopace chainrings/cranksets whatever you call them, I had never even seen nor heard of them, it was only when servicing the chainring, I noticed it was oval and I thought hey that sounds like a good idea, but lets see what happens in practise. As soon as I took it for a spin, I noticed immediately from 1st gear and going through the gears, I could get to full speed much faster and it seemed effortless, also I noticed I could go way faster on this bike and I mean seriously fast, as I found out a couple of high-speed crashes and near misses later, it wasnt until the impact and how long it took for me to come to a standstill, I realised how fast I was going, my speedometer was broken in the first crash so dont know how fast I was going and I havent seen the math on what effect or advantages these Biopace chainrings have but I know for sure it was definately multiplying my impetus by what seems at least 10 fold and it was not due to my fitness levels as I was very unfit, it was definately down to this Biopace chainring, so I started taking on different challenges in an effort to prove it for myself and I found to my surprise that I could do a most of the steep ascents, without even getting of the seat, it was almost effortless and when I come to some seriously steep ascents, where I had to get off the seat and use my bodyweight, that was also effortless in comparison to another non biopace mountain bike I tried all the same ascents on a hire bike and I had to get off, I couldnt make it up most of them and it was extremely intense on my joints especially my knees.
    Its now been over 10 years since I got this Specialized and as far as I am concerned I have proven Biopace chainrings work beyond all doubt and they have had no detrimental affect on my knees or anything and believe me playing football and jogging and doing 40 mile charity jogging challenges and considering my age and my knees and joints are always under varying and constant pressures.
    So I cannot believe these Biopace chainrings went out of favour and production, all this theory, for and against, blah blah blah, I didnt read or listen to a word of it, all I know that is that in reality, its a no brainer, having a Biospace chainring is definately an advantage in all situations, flat or mountainous, they should now be the standard and anyone who has anything negative to say about them has not tried and tested them for as long and consistently as I have. What needs to happen is that some University puts Biopace up against standard cranksets does all the math and performs all the neccesary practical scientific tests and I am sure they would prove beyond doubt that Biopace are superior.

    Reply • May 3 at 5:56 am

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